1. Field of the Invention
The present invention generally relates to a process and system for removing extraneous resist material on a semiconductor wafer which results from the dispensing of the resist material onto the semiconductor wafer. The present invention is more particularly related to the removing of extraneous resist material on a semiconductor wafer which is formed when a wet edgebead operation is performed on the semiconductor wafer to remove "edgebeads," the extraneous resist material which is formed during the wet edgebead operation.
2. Background of the Related Art
Photolithography, the process of exposing resist coated semiconductor wafers to develop patterns in the resist material, is currently performed or implemented with a photoresist type material. A photoresist type material is a solution of polymers bonded to photoactive compounds. The photoactive compounds are exposed to light according to a predetermined pattern, and developed forming patterns in the resist material. The developed patterns are used in the forming of devices in the semiconductor wafer.
Photoresist material is typically deposited on the semiconductor water as a sticky material which when dried becomes brittle. Accordingly, the photoresist material has a tendency to flake and create small particles which can infiltrate and destroy devices embedded or formed in the semiconductor wafer. Since the resist material may significantly affect the operation of a semiconductor chip, a great deal of attention has been given to ways of preventing the resist material from creating these small particles or flakes which can destroy the devices in the semiconductor wafer. For example, it is generally understood that when the semiconductor wafer is coated with the resist material, small balls or beads of photoresist remain stuck to the edges of the wafer. These beads are typically called "edgebeads." The edgebeads can flake and create various defects in the semiconductor wafer as described above. Thus, the edgebeads can significantly reduce the yield of properly operating semiconductor wafers, increasing cost of manufacture.
To combat problems resulting from the normal edgebeads formed during the coating of the semiconductor wafer with resist material, many manufacturers incorporate a "wet edgebead operation" which is used to remove the edgebeads from a semiconductor wafer. The wet edgebead operation consists of dispensing solvent at the wafer edge to dissolve the edgebeads from the upper edge, back and side of the wafer. By performing the wet edgebead operation, the edgebeads can be removed to some extent, thereby reducing or minimizing the flaking of resist material and the formation of defects in the semiconductor wafer.
Even though the wet edgebead operation has been previously performed, semiconductor wafers have still encountered significant device failures. Accordingly, it is desirable to determine the cause of the semiconductor failures. Once the cause of the semiconductor failures is determined, it is also desirable to formulate a solution to correct the semiconductor failures.
It is further desirable that any solution or process used to correct the semiconductor failures be implemented in a continuous process, and also be incorporated in or used with the existing process of depositing resist material onto the semiconductor wafer.